Nyhan and his collaborators, Andrew Guess of Princeton University and Jason Reifler of the University of Exeter, say their research offers the first hard data about the role fake news plays in Americans’ information diets during the final weeks before Nov. 8, 2016.

“It’s the first data we have that measure who actually saw fake news, rather than how often it was shared on social media or how many people think they saw it when asked after the fact,” Nyhan said over the phone on Tuesday.

An analysis of web traffic data collected from 2,525 Americans found that fake news — intentionally false stories created for profit or political manipulation by a range of sources, including Russian-backed content farms — was mostly read by Americans furthest to the right of the political spectrum.

The study, conducted using weighting methods and a sample size similar to top political polls, found that the 10 percent of Americans with the most conservative media diets read about 60 percent of the fake news stories.

But the results also highlighted some popular misconceptions; for instance, that people who saw fake news had little access to more reliable information. To the contrary, Nyhan’s study found, consumers of false stories tended to be avid readers of mainstream news sources, too.

“There’s a story that people tell about fake news where it was read by people in place of real news,” said Nyhan, who also is a contributor to The New York Times’ Upshot blog. “We find no evidence that fake news is crowding out hard news.”

The researchers also discovered that fact-checkers’ efforts to debunk popular fake stories — one of which claimed, for instance, that Donald Trump had been endorsed by the pope — rarely reached the people who read them, leading to what Nyhan called a “targeting problem.”

Nyhan studies political misperception and misinformation in Dartmouth’s Department of Government, and some other recent research of his has touched on fake news and fact-checkers’ efforts to combat intentionally false, or merely misleading, information.

Previous collaborations of his with Reifler, in 2010 and 2014, found that exposing people to corrective information can sometimes backfire, leading them to embrace factually incorrect beliefs even more strongly. Other research, including some more recent surveys from Nyhan, has offered more promising results, with the caveat that people’s reaction to fact-checks tends to depend on their political views.

In Tuesday’s interview, Nyhan noted that the methodology of this new study, which was posted online last week, had some limitations.

Although 2,525 Americans consented to have their web traffic monitored through the online research firm YouGov, this did not include their activity on social media, and their use of mobile platforms was only partially recorded.

Besides seeing how often participants visited Facebook or arrived at a news site from Facebook, which was by far the biggest vector for fake news, the researchers were unable to reconstruct exactly what Facebook showed its users. And the social media giant is keeping that data close to the chest.

“That’s certainly an important limitation,” Nyhan said, although he added that he expected fake news viewing trends to be the same on mobile and social platforms — high readership among avid consumers of news who swing far to the right, with little exposure to fact-checks.

Nyhan also noted that his study had found a correlation within the fake news readership between political beliefs and choice of outlet: supporters of Democratic presidential nominee Hillary Clinton tended to read more pro-Clinton false articles, and vice versa with Trump.